Electrified train transit systems are popular in urban settings due to their low level of pollution and high efficiency and reliability. Such transit systems typically feature an electric locomotive that pulls train cars for carrying passengers and that receives power from an overhead contact system. Overhead contact systems typically feature messenger and contact wires that are suspended over the track that the electric train cars travel on. The top of the electric locomotive is provided with a pantograph which contacts the contact wire so that the locomotive receives power.
The messenger and contact wires are typically suspended by a cantilever assembly, such as the one indicated in general at 8 in FIG. 1. As illustrated in FIG. 1, the cantilever assembly includes two or more insulated, rigid cantilever arms, illustrated at 10 and 12, that are attached by their proximal ends via members 14 and 16 to a pole 18 positioned next to the tracks. The distal end of the lower cantilever arm 12, which features a tilted orientation, is typically attached to the underside of the upper cantilever arm 10, which is positioned in a generally horizontal orientation. As a result, the lower cantilever arm provides support for the upper cantilever arm. A messenger saddle 20 is typically positioned at the distal end of the upper cantilever arm. A steady arm 21 is typically attached by its proximal end to the lower cantilever arm, and an insulated swivel clamp 22 for the contact wire is typically positioned at the distal end of the steady arm. The messenger passes over the saddle 20 and its ends are connected to the contact wire by hangers to form a bridal assembly where the contact wire is suspended by both the swivel clamp 22 and the messenger cable.
As is clear from the above, the cantilever assembly, which includes the upper and lower cantilever arms and the steady arm, are critical components for securing and maintaining contact and messenger wire heights and locations in an overhead contact system. Steel pipe is typically used for the upper and lower cantilever arms and the steady arm. This makes the components heavy and difficult to handle and install. A need therefore exists for a cantilever and steady arms that provide a reduction in weight.
As is also likely apparent from the above, the cantilever assembly must be properly configured for optimal performance. In addition, a large number of cantilever assemblies must be assembled and installed for an overhead contact system. As illustrated in FIG. 1, prior art cantilever assemblies typically use clevis pipe clamps 24 and 26 to secure the distal end of the lower cantilever arm to the underside of the upper cantilever arm and to secure the proximal end of the steady arm to the lower cantilever arm. Such clamps feature a number of different parts that are difficult to handle during installation and may become easily separated and lost. In addition, assembly and tightening of the clamps is time consuming. A need therefore also exists for a fastening bracket for the cantilever and steady arms of a cantilever assembly that is quick and easy to install and that remains as a single assembly during installation.